Conventionally, there have been proposed various types of seatbelt retractors which remove the slack of webbing in case of an emergency, such as vehicle collision or the like.
For instance, there has conventionally been used a seatbelt retractor equipped with a forced locking mechanism which functions as follows. In a case where a gas generating member of a pretensioner mechanism activates in response to vehicle collision, a piston inside a pipe cylinder moves upward from its normal state so as to rotate a pinion gear body. Thereby, teeth on a pinion gear portion of the pinion gear body come in contact with a push block disposed inside of a base block body and push the push block outwardly. Consequently, the push block is further pushed outwardly by a block urging spring so that a rotating lever is rotated. Further on, a lower end portion of the rotating lever is disengaged from a tip end portion of a gear-side arm. Thereby, the gear-side arm is rotated in outward direction by the urging spring, and simultaneously, a mechanical-side arm is rotated through a coupling shaft. As a result, rotation of the mechanical-side arm causes a pawl to get engaged with a ratchet gear of a take-up drum (for instance, refer to Japanese Laid-open Patent Publication No. 2009-241863).